If you have an energetic dog, it can be difficult to keep them entertained and to give them the exercise they need. I have an Australian Shepherd myself and I have a hard time giving him enough play time in between writing these articles for you all to enjoy. Fortunately, lots of dogs — mine included — love to play fetch and will happily chase balls until they collapse from exhaustion. But hurling those balls yourself can get tiring. That’s why Connor Bensor designed this fantastic 3D-printed tennis ball launcher that can keep dogs entertained for hours and now I want to build one for my pup.
This machine works a lot like the conventional tennis ball launchers that tennis players use for practice. Balls are dropped into the machine, which has wheels spinning at a high speed. As soon as a ball makes contact with those wheels, it is shot out for a dog to retrieve. But the tennis ball machines on the market today are fairly expensive; they start at around $300, which is quite a lot of money to spend on a dog toy. Benson’s machine can be built for far less by using affordable off-the-shelf parts. It doesn’t seem to be capable of shooting a ball as far or fast as a commercial tennis ball machine, but it is perfectly adequate for playing fetch with your dog in the backyard or a park.
The 3D-printed structure of this machine is quite simple and is roughly (ruffly?) the size of a tissue box. Balls are dropped in from the top and then rest on top of a stopper mechanism. An Arduino Nano board monitors an Adafruit proximity sensor next to that stopper. When a ball is detected, the friction wheels (which are also 3D-printed) are spun up using a pair of powerful Turnigy brushless DC motors that are controlled via Turnigy ESCs (Electronic Speed Controllers). Once the wheels are up to speed, the stopper mechanism is released by a small hobby servo motor. The ball then drops down into the wheels and goes flying. Power comes from a RC-style battery pack. It seems like this design would benefit greatly from the additional of a hopper, so multiple balls can be launched without a human needing to feed them to the machine. But even as it is, this machine is great for keeping good boys occupied and happy.